Dairy Bars / Drive-Ins near I-95 - GA exits 1-2 or north Florida

Dairy Bars / Drive-Ins near I-95 - GA exits 1-2 or north Florida

Looks like we'll be going back to south Georgia in early July and will be taking a day trip to Cumberland Island. I may get a chance to explore the towns of Kingsland or St. Mary's or (less likely) Yulee or Fernandina Beach, and would love to find a really old dairy bar or drive-in or old (1950s/1960s) independent fast food joint. Anybody familiar with these towns? I'm not expecting much, but someplace to get a burger and a milkshake would be lovely.